I have a stone arch stuck to the wall above my wood burning stove. One of the stones has fallen off and I’m not sure how to repair it. Any help would be greatly appreciated.

The stone that fell weights approx 15 lbs and is roughly 14x17x7/8”.

The stones seem to be attached to the wall with some kind of cement (some of it came loose or off when the stone came down but most of it is still there). The cement itself is about as think as the stone.

Under the cement on the wall seems to be a kind of metal arch that it’s adhered to.

Any suggestions how to put this stone back up? Should I chisel down all the cement that was behind it and then use something to replace it and put the stone back up? What should I use for the cement? When I put it up how do I keep it up there until it can stay on it’s own? Sorry I’m unfamiliar with all of this and google searches weren’t finding the right info.

As you predicted, you will need to remove most of the d mortar from both the wall and the backside of the stone. Use a small cold chisel and a hammer. This is required for a good bond and so that the stone is at the same level as the others.

Mix a small batch, make sure it's not too wet and smear it on the backside of the stone and on the wall. Apply the stone and hammer it with a rubber mallet until it is level with the others. Clean up any mortar that has leaked out.

Now the hard part, you will need to secure the stone until it dries. Probably the easiest would be a small piece of wood wedged under the stone to hold it up and use painters tape to hold it against the wall.